Plunger switch with pivoted actuator

Abstract

A normally open plunger switch capable of closing upon initial movement of the plunger, and allows overtravel of the plunger at least to the extent of one half the depth of the switch. The actuator is pivoted in the case in the manner of a conventional rocker/actuator and it is coupled to the plunger by projecting portions on both it and on the plunger to provide for both these features.

We claim: 
     
       1. An electric switch mechanism comprising; an upwardly open switch case having a bottom wall and side walls integrally connected to one another, at least two fixed contacts in the bottom wall and a movable contact adapted to bridge said two fixed contacts in a closed switch condition and to be held in contact with only one of said fixed contacts in a switch open condition, actuator means pivotally received in said switch case and movable between opposed limit positions corresponding to said respective switch conditions, said actuator means coupled to said movable contact to achieve said switch open and switch closed conditions in response to pivotal movement of said actuator means, a cover for said switch case, said cover spaced above said bottom wall, a plunger slidably received in an opening provided for it in said cover, said plunger movable between upper and lower limit positions spaced vertically from one another by at least one half the said spacing between said bottom wall and said cover said actuator means having laterally projecting axial portions pivotally received in aligned openings provided therefor in said switch case side walls, said actuator means being covered by said case cover and having radially opposed projecting abutments for engaging the underside of said cover in said limit positions respectively for said actuator means, said acutator means having a projection (20h) adapted to being engaged by said plunger to move said actuator means only during initial downward movement of the plunger, said plunger being movable downwardly beyond said initial movement without corresponding movement of said actuator means, and biasing means urging said plunger upwardly, one of said radially projecting abutments having a portion (20f) engaged by a plunger portion (30b) to reset said actuator as said plunger moves upwardly into said upper limit position.   
     
     
       2. An electric switch mechanism comprising: an upwardly open switch case having a bottom and side walls integrally connected to one another, at least two fixed contacts in the bottom wall, and a movable contact adapted to bridge said two fixed contacts in a closed switch condition and to be held in contact with only one of said fixed contacts in a switch open condition, actuator means pivotally received in said switch case and movable between opposed limit positions corresponding to said respective switch conditions, said actuator means coupled to said movable contact to achieve said switch open and switch closed conditions in response to pivotal movement of said actuator means, a cover for said switch case, said cover spaced above said bottom wall, a plunger slidably received in an opening provided for it in said cover, said plunger movable between upper and lower limit positions spaced vertically from one another by at least one half the said spacing between said bottom wall and said cover, said actuator means is pivotally mounted for movement on a laterally extending pivot axis which is generally centered in said switch case and wherein said plunger moves along its vertical axis in radially spaced relation to said actuator pivot axis, said plunger and actuator means having primary interactive portions engageable with one another such that incremental initial movement of said plunger from its upper position toward its lower position causes said actuator means to pivot from one limit position to an opposed limit position, said plunger interactive primary portion being movable past said interactive primary portion of said actuator means as said plunger movement continues toward its lower position, said plunger and actuator means having secondary interactive portions engageable with one another during terminal upward movement of said plunger adjacent said upper position as said plunger moves from said lower position into said upper position.   
     
     
       3. The switch mechanism of claim 2 wherein said plunger has a lower end defining said secondary interactive portion, said plunger lower end comprising laterally opposed cross bar arms, said switch case side walls having grooves slidably receiving the ends of said cross bar arms. 
     
     
       4. The switch mechanism of claim 3 wherein said actuator means has radially projecting abutments for engaging the underside of said cover in one and an opposed limit position corresponding to said two switch conditions, one such radially opposed projecting abutments defined by two laterally spaced arms of said actuator means, said spaced actuator arms also defining said actuator defined secondary interactive portion thereof. 
     
     
       5. The switch mechanism of claim 4 wherein said actuator means has a protuberance located in the path of downward movement of said plunger and defining said primary interactive portion thereof, said plunger having a lower end defining its primary interactive portion for engaging said protuberance, and said protuberance located vertically below said laterally spaced actuator arms and in centered relation therebetween. 
     
     
       6. The switch mechanism of claim 5 wherein said actuator includes a depending portion defining a downwardly open cavity and a pin slidably supported in said cavity so that its lower end is continuously coupled to said movable contact to move this contact across the upper end of said one fixed contact, said movable being supported by said second contact in the switch closed condition and by said switch case bottom wall in the normal switch open condition. 
     
     
       7. The switch mechanism of claim 6 wherein said actuator means has laterally opposed axle defining portions pivotably supported in aligned openings provided in said switch case side walls, and biasing means acting between said switch case and said plunger to urge the latter upwardly toward said upper limit position corresponding to a normal switch open condition. 
     
     
       8. The switch mechanism of claim 2 wherein said case cover has an underside which is closely spaced with respect to said pivot axis for said actuator means, said actuator means having radially opposed projecting abutments for engaging said cover underside in said one and said opposed limit positions respectively. 
     
     
       9. The switch mechanism of claim 8 wherein one of said radially opposed projecting abutments is defined by two spaced arms on said actuator means, said spaced arms defining said secondary plunger engageable portion of said actuator means, said plunger defined secondary actuator engageable portion comprising a laterally extending cross arm located adjacent the lower end of said plunger and engageable with the said arms on said actuator means, and biasing means acting between said case and said plunger to urge the plunger toward said upper position. 
     
     
       10. The switch mechanism of claim 9 wherein said actuator means has laterally projecting axle portions pivotally received in aligned openings provided therefor in said switch case side walls, and said cover having laterally projecting tabs received in corresponding openings provided in said case to secure said cover to said case. 
     
     
       11. The switch mechanism of claim 10 wherein one of said fixed contacts is located below said actuator pivot axis in centered relationship in said case, said case having an elongated rectangular configuration with said plunger on one side of the center of the case and with the second fixed contact located on the other side thereof, said movable contact supported by said one center fixed contact for pivotal and sliding motion relative thereto, said movable contact selectively engageable with said second fixed contact as said actuator is moved into said opposed limit position by said plunger. 
     
     
       12. The switch mechanism of claim 11 wherein said actuator means has a downwardly open cavity, a pin slidably received in said cavity and having a lower end received in an upwardly open recess in said movable contact, a spring acting between said pin and said actuator means to maintaining said pin lower end in coupled relationship to said movable contact and achieve coupled sliding movement of said movable contact in response to pivotal actuator movement. 
     
     
       13. The switch mechanism of claim 10 wherein said cover defined tabs are located adjacent to said actuator defined axle portions, said switch case side walls defining adjacent openings to receive said adjacent tabs and axle portions respectively. 
     
     
       14. The switch mechanism of claim 13 wherein said movable contact has a free end portion supported on said second fixed contact in the closed switch condition and wherein said movable contact has an opposite end portion opposite said free end portion and adjacent said pin recess, and an upwardly extending web integrally formed in the bottom wall of the switch case for supporting said opposite end portion of said movable contact in the open switch condition.